Variation in soil penetration resistance as a function of soil moisture under crop management systems¹

ABSTRACT

The objective of this study was to monitor the temporal variation in penetration resistance (PR) after soil saturation under different management systems in three areas of the Cerrado biome: two in no-till systems (NT with 3 and 10 years of implementation) and one of crop-livestock integration (CL with 9 years of implementation) with soybean/forage succession. Four transects were delimited in each area. The delimited area was saturated and the PR measurements were performed daily for 11 days at 10 transect points, up to 0.40 m of depth. Soil moisture was determined with PR measurements, soil hydraulic conductivity, and organic carbon. PR values were more significant in the 0.10 - 0.20 m layer than in the 0.0 - 0.10 and 0.20 - 0.40 m layers. The NT-3 area showed a lower PR value (1.65 MPa) than the area under NT-10 and CL-9, with 2.48 and 2.69 MPa, respectively. Thus, critical soil moisture values, that is, soil moisture values most susceptible to soil compaction were determined. Thus, in the NT-3 area, the critical moisture was 0.20 kg kg^-1, in the NT-10, ranged from 0.19 - 0.20 kg kg^-1, and in the CL-9, between 0.23 and 0.20 kg kg^-1. Monitoring soil moisture can prevent management operations from restricting root growth.

Key words
No-tillage; Integrated crop-livestock; Hydraulic conductivity.